modified CMakeLists and fixed includes

includes/learnopengl/camera.h

@@ -4,7 +4,7 @@
 #include <vector>
 
 // GL Includes
-#include <GL\glew.h>
+#include <GL/glew.h>
 #include <glm/glm.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 
@@ -130,4 +130,4 @@ private:
         this->Right = glm::normalize(glm::cross(this->Front, this->WorldUp));  // Normalize the vectors, because their length gets closer to 0 the more you look up or down which results in slower movement.
         this->Up    = glm::normalize(glm::cross(this->Right, this->Front));
     }
-};
+};